Ranking the NBA's 5 Most Surprising Injury Replacements

The NBA regular season stretches across six months of the year—seven or eight including the playoffs—but can end at a moment's notice with a single injury.

Just ask the Chicago Bulls and Oklahoma City Thunder, who lost Derrick Rose (2012) and Russell Westbrook (2013) to torn ACLs in the playoffs in consecutive seasons. Both began the postseason as top seeds; the Bulls bowed out in the first round to Philadelphia, while the Thunder survived their first series with Houston before falling to Memphis in five games.

Perhaps not coincidentally, both players re-injured themselves this season, forcing their teams to use that old "next man up" sports adage. And while a team is almost never the same—usually for the worse—when one of its core members misses significant playing time, it provides an opportunity for relatively unknown players to establish themselves.

The basketball gods have been particularly merciless this season. According to CBSSports.com, 11 players have been officially declared out for the season, five more are out indefinitely, and another 10 won't return until March or later. Seventeen were starters or filling in for an injured starter.

With so many key players missing time, a number of unsung roster fillers have been thrust into big minutes. Some have balked at the responsibility, maintaining a so-so level of play that suggests they should return to the bench.

A select few, however, have risen to the challenge, doing their best to imitate the guy in street clothes whom the fans would rather see on court.

This list evaluates players based on a combination of their numbers before this season, the production they were asked to replace and the impact they had with increased minutes. A bigger sample size also helped players move up the list.

Without further adieu, here are this season's best injury replacements in the NBA.

Honorable Mentions

With a rash of injuries, most of San Antonio's bench qualifies for this list. Boris Diaw, Marco Belinelli and Cory Joseph have all started at least a dozen games. In fact, Joseph has been the nominal replacement starter for the eight games that Tony Parker missed.

But Patty Mills, despite starting just one game all year, has been the one to pick up the slack. In those eight games the Spurs played without Parker, Mills elevated his play. He scored 18.3 points per game in 26.8 minutes, as the Spurs compiled a 7-1 record without Parker. Thrice, Mills led the team in scoring from the bench in victories over Portland, the Clippers and Milwaukee.

Unfortunately, he has a relatively small sample to work with. Though his minutes jump 62 percent when Parker sits, Gregg Popovich still keeps Mills to sixth-man minutes.

Nick Calathes, Memphis Grizzlies

Although he played college ball at the University of Florida, few people outside of the Memphis press knew Nick Calathes before Mike Conley went down with an ankle sprain on January 31. In 34 prior games off the bench, he made little impact. He played 12.6 minutes per game, averaging three points and 2.2 assists per game.

But in just seven starts, he contributed 14.7 points and 4.9 assists in guiding the Grizzlies to a 4-3 record. Calathes, who plays for the Greek national team, made enough of an impact to earn 19 minutes of playing time in Conley's first game back from injury. Again, he suffers from a small sample size and misses out on joining the top five.

Reggie Jackson, Oklahoma City Thunder

Kevin Durant deserves credit in making up for 30 games of Russell Westbrook's lost production. But we won't go there since he's already on the short list for MVP. Reggie Jackson took over the "point guard" position, though Durant did most of the ball-handling, scoring and assisting.

Jackson's minutes went from 25 to 31.6, while his scoring barely increased from 12.6 to 14.4 points and his assists went from 3.3 to 4.9. Oklahoma City has gone 22-8 without Westbrook, but chalk it up to the Slim Reaper's determination to win the MVP.

Brian Roberts is one of just 19 players from the University of Dayton to ever play in the NBA. In his second season, he is the first Flyer to play significant minutes since Jim Paxson retired in 1990.

Thrust into the starting lineup when Jrue Holiday suffered a stress fracture in his right tibia, Roberts has filled in admirably. Holiday left the Pelicans with a 15-19 record; they've gone 8-11 since for a nearly identical winning percentage.

From Tyreke Evans and Eric Gordon underperforming to Ryan Anderson and Jason Smith missing significant time to injury, the Pelicans' losing woes go deeper than Roberts' inability to equal Holiday's production. And he's shown flashes of being a legitimate first guard off the bench down the road in New Orleans.

Take his 19-point, four-assist performance in a losing effort to San Antonio as an example. The video above shows his vision in transition, his comfort with the pull-up jumper and quickness to get to the hoop and draw contact.

Not to mention his shooting range. Over the entire season, Roberts is shooting .412 from behind the arc, tied with D.J. Augustin for 15th-best in the NBA. As a starter, his clip from deep jumps to .463, within reach of Kyle Korver.

He has done a good job taking care of the ball as well. His turnover ratio as a starter is 10.6, which puts him in the middle of the pack among starting point guards. He's had eight games with one or no turnovers since taking over the point.

"(Roberts) has been steady for us,” coach Monty Williams said. “The Memphis (win Jan. 20) was an indicator of how well he can play when he’s knocking down shots and finding guys. And his defense was really good against (Grizzlies point guard Mike) Conley, getting over pick and rolls. But he’s been steady for us, and we need that every night.”

While the Pelicans continue their losing ways, Roberts has come a long way in a short period of time. He averaged just 7.1 points and 2.8 assists in 17 minutes per game as a rookie.

Blake Griffin put on his best Durant-without-Westbrook impersonation in the 18-game stretch that Chris Paul missed. Griffin raised his scoring average by five points and added another full assist per game as the Clippers went 12-6 without their star playmaker.

Darren Collison, however, did not simply fill Paul's minutes as Reggie Jackson did for Westbrook in Oklahoma City. In nearly double the minutes he received as a reserve, Collison raised his scoring by 65 percent while tripling his assist output—both numbers topped his single-season career highs.

Those numbers still lag in comparison to Paul's. But like Roberts in New Orleans, Collison did a great job keeping possession for Los Angeles. As a reserve, his assist-to-turnover ratio was 1.7, better than only three other point guards in the NBA. When he moved into the starting lineup, that ratio jumped to 2.9, which would place him 11th among ball-handlers.

While he isn't the type of player to take over a game, he took advantage of his opportunity, and it didn't go unnoticed:

In 34 games before Paul's injury, Collison scored 15 or more points just twice. In those 18 games as a starter, he topped 20 points four times, including his best CP3 impression against the Magic in the video above.

Sadly for Collison, he's returned to his previous role in the three games since Paul's return.

Though they look similar on a TV screen hanging behind a bar, comparing D.J. Augustin to Derrick Rose is nothing short of hyperbolic.

While Rose owns an MVP award, Augustin is playing for his fourth team in six seasons.

Yet Augustin has been nothing short of a revelation in leading the Bulls to a 21-13 record since arriving, as they experience in Life Without Rose Part II.

The best part of the story is that the Bulls plucked the University of Texas product out of unemployment. He spent the first 10 games of the season in Toronto, playing eight minutes per game before receiving his walking papers.

And while Kirk Hinrich may be the starter, the Bulls ebb and flow with Augustin.

He's playing the same minutes as Hinrich while outscoring, outshooting and out-assisting him. In fact he's producing numbers very close to the career year he had with the Charlotte Bobcats in 2010-11.

And the guy can flat-out shoot, something Chicago sorely lacked. See the video for proof.

January was particularly good to Augustin. He averaged 16.1 points and 6.0 assists as the Bulls went 11-4. That month included a run of six starts in place of the injured Hinrich, where Augustin led the team in scoring three times.

In nine total starts, he played a Luol Deng-like 38.2 minutes while scoring nearly 18 points and dishing 6.4 assists.

Like Augustin, Kendall Marshall went from one team's trash to another's treasure.

Phoenix included Marshall as part of the Emeka Okafor-Marcin Gortat trade with Washington, and the Wizards promptly waived him into unemployment.

Injuries to both Steve Nash and Steve Blake left the Lakers in need of a point guard. Enter Marshall stage right.

Since being inserted into the starting lineup, Marshall has been a bright spot on a dark Lakers season. Though he doesn't qualify on ESPN's statistical standards in terms of games played or assist pace, his 12.1 dimes per game as a starter would put him above Chris Paul as the league's top assist man. His 3.45 assist-to-turnover ratio is sixth-best. Observe his passing prowess above.

Kendall Marshall now has 7 games of 14+ assists, tied for most in the NBA this year

Marshall hasn't been able to effect much winning for the Lakers, who might be the league's most injury-plagued team. But with Nash on the wrong side of 40 and Blake moving to NorCal, Los Angeles may have found its point guard of the future.

Also like Augustin, Marshall is a lethal perimeter shooter. He leads the NBA with a .477 clip.

Phoenix has had a roller-coaster ride of a season. Originally picked to finish toward the bottom of the Western Conference, the Suns jumped out to an 18-11 record before Eric Bledsoe went down with a right knee injury.

Bledsoe, finally freed from his bench role with the Clippers, was in the midst of a career year. Meanwhile, Gerald Green had never started more than 26 games since joining the league in 2005 and played more than 50 games just twice in seven seasons playing for six different teams. He also had several D-League and overseas stints.

That's why his play as a starter has been such a surprise for coach Jeff Hornacek.

Much of the Suns' continued success—they sit sixth in the West with a 33-21 record—is due to Goran Dragic's incredible play this season, as he has taken over all of the ball-handling. But Green has made a stamp on the season in his own right.

He has led Phoenix in scoring six times and has eight games with more than 20 points—including a career-high 36 in a 112-107 win over Denver last week.

In Bledsoe's absence, Green has helped the Suns to a 18-14 record with big wins over Indiana (twice), Golden State and San Antonio as they fight to stay afloat in the playoff race.

Lucky for the Suns, Bledsoe is rumored to return to practice next week, per Paul Coro of AZCentral.com, and he should have plenty of time to prep for the playoffs. In the meantime, they can turn to Green for reliable production.